Space Weather Conditions at the Time of the Galaxy 15 Anomaly

17 Pages·2015·2.24 MB·English

by  Bill Denig

Space Weather Conditions at the Time of the
Galaxy 15 Anomaly
NOAA Tiger Team
• W. F. Denig (NGDC)
• J. C. Green (SWPC, now NGDC)
• D. C. Wilkinson (NGDC)
• J. V. Rodriguez (CIRES @ SWPC)
• H. J. Singer (SWPC)
• P. T. Loto'aniu (CIRES @ SWPC)
• D. A. Biesecker (SWPC)
• W. Murtagh (SWPC)

Galaxy 15 Satellite
Presented at the
Photo Credit: Orbital Sciences
2011 Space Weather Workshop
26-29 April 2011
Boulder, CO
OUTLINE
Space Weather Conditions – 05 Apr 10
Space Weather describes changes in the
interconnected system from the Sun to Earth
This presentation follows space weather conditions progressing
from the sun to near the Galaxy 15 location showing:
1. Events that occurred at the sun
2. Resulting global changes in the near-earth space environment
3. Local changes near Galaxy 15 in the energetic charged particles that
can cause satellite charging and electronic component failure
Summary
 Solar activity was elevated but not remarkable
 Global geomagnetic activity described by the AL auroral electrojet
index and Kp were extreme. Other SWx indices were more moderate
 Local measurements near Galaxy 15 show that a large geomagnetic
substorm occurred 48 minutes prior to the anomaly. The substorm
caused remarkable increases in the measured local flux of energetic
particles known to cause surface or internal satellite charging
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Background (1 of 2)
Galaxy 15 Satellite Anomaly - Impacts
08 Apr 2010 – Intelsat reports that the Galaxy 15
stopped responding to ground commands
(Anomaly time: 05 April @ 09:48 UTC)
10 Apr 2010 – FAA predicts erosion of WAAS
capability due to Galaxy 15 failure
20 Apr 2010 – Orbital attributes the loss of
Galaxy 15 to space weather
30 Apr 2010 – Intel reports Galaxy 15 still adrift
and threatens nearby satellites (i.e. frequency
interference)
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Background (2 of 2)
Operational Timeline
Operational Timeline – Universal Time (UT)
April 3, 2010
09:54 B7 solar flare (sunspot region 1059)
10:33 CME first visible
22:04 SWPC Daily Forecast issued
– Notes Flare and Coronal Mass Ejection (CME)
– Geomagnetic quiet expected: 04-05 April
April 4
22:01 Daily Forecast issued (left text)
– Flank of CME may contribute to elevated activity
on April 7
April 5
05:33 Warning issued: K=4
05:44 Alert issued: K=4
08:04 Warning issued
– Sudden Impulse (CME hits ACE @ 07:56 UT)
09:16 Warning issued: K=5
09:17 Alert issued: K=5
09:22 Alert issued: K=6
09:48 Galaxy 15 anomaly
09:56 Alert issued: K=7
SWW – 26-29 April 2011
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Space Weather Conditions
1. Events at the Sun (1 of 2)
Solar activity prior to the Galaxy 15 anomaly on April
05 at 9:48 was elevated but unremarkable.
On 03 April @ 9:54 UT (2 days prior to the anomaly) a solar B7 flare was
observed by the NOAA GOES-14 X-Ray Sensor (XRS)
– Flares of this intensity are not usually associated with intense space weather
– In solar cycle 23 there were >14,000 flares more intense than a B7-level flare
– There have already been 278 flares more intense than B7 in the new cycle
– Source of the flare was decaying active region 1059 (S22W15) with 4
sunspots
Satellite Eclipse B7 FLARE
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Space Weather Conditions
1. Events at the Sun (2 of 2)
April 03 @ 10:33 UT ~30 minutes after the flare an earthward SOHO/LASCO
directed coronal mass ejection (CME) was observed
– SOHO/LASCO imager showed a modest partial Halo event
– Side view of the CME from the NASA STEREO COR2 instrument
indicated that it was moving southward and only the ‘edge’ would
graze earth
– Measured plane of sky speed was 512 km/s
– Moderate speeds and ‘edge’ impacts such as these typically cause
weaker, shorter duration geomagnetic storms
NASA/ESA
– Solar cycle 23 had ~500 faster Earth directed CME’s
STEREO COR2
This event was classified as a moderate CME ejected from
an otherwise quiet sun
– F10.7 was 77 sfu, the sunspot number was 27 and the x-ray
background was a modest 3.9x10-8 Watts m-2
EARTH
– At solar maximum, F10.7 is expected to be about 150 sfu and
the sunspot number to be at least 3x greater
NASA
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Space Weather Conditions
2. Global Environment At Earth (1 of 2)
Galaxy 15 anomaly
April 05 07:56 UT – Nearly 2 days
CME detected
after the CME lifted off from the
by ACE
sun, it was observed by the NASA
ACE satellite upstream of earth
– It takes ~30 minutes for the solar
wind to propagate from ACE to Earth
– The solar wind magnetic field turned
southward (negative)
– The solar wind speed increased
from ~500 to >700 km/s

Such solar wind conditions often result in a
moderate geomagnetic storm
Note: ACE is the NASA Advanced Composition Explorer located in a halo
orbit near the L1 sun-earth Lagrangian point approximately ~1.5x106
km in the sunward direction. Plot shows solar wind parameters
Data Source: NASA Omni
observed at ACE, time-shifted to Earth.
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Space Weather Conditions
2. Global Environment At Earth (2 of 2)
Some (but not all) global geomagnetic activity indicators were
extreme immediately prior to the anomaly
01 Oct 05 to 01 May 10
Currently only quick look plots are available for April
AL index was <-2000 nT prior to the anomaly.
Larger values observed only once previously
during Galaxy 15 lifetime (launched: 13 Oct 05)
Kp index reached 7.7 prior to the anomaly –
larger values were observed only once
previously during the Galaxy 15 lifetime
? However, Dst index reached -32 nT prior to
anomaly indicating only a moderate storm –
similar to many previously observed levels
during the Galaxy 15 lifetime
Data Source: Kyoto World Data Center & German Research Centre for Geosciences 9
Space Weather Conditions
3. Local Environment At Galaxy 15 (1 of 4)
April 05 @ 09:00 UT: GOES magnetometers and particle instruments showed a major
reconfiguration of the magnetosphere indicative of a substorm and injection of energetic
particles into the nightside, geosynchronous orbit location
Galaxy 15 (133 W) Anomaly 09:48 UT
Satellite Locations
Eclipse
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Space Weather Conditions
3. Local Environment At Galaxy 15 (2 of 4)
Surface Charging: Electron Environment (Low-to-Medium Energy Electrons)
 April 05 @ 9:00 – 48 minute prior to the Galaxy 15 anomaly the 40-to-475 keV
electron flux increased at GOES 14 and 15
– 75-to-475 keV electron flux was the highest observed since GOES 14 was turned on in July
2009 and since GOES 15 was turned on in April 2010
– High electron fluxes are notable although surface charging potentials cannot be accurately
estimated without lower energy (<40 keV) particle measurements and detailed modeling of
their interactions with specific satellite surface materials
Galaxy 15 anomaly
GOES 14 -----
Satellite Locations
GOES 15 -----
Note: Multiple curves for each GOES satellite correspond to different telescope “look” directions
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